Many seasonally breeding species, including Siberian hamsters (Phodopus sungorus), exhibit seasonal variation in sickness responses. One hypothesis regarding the mechanism of this variation is that sickness intensity tracks an animal's energetic state, such that sickness is attenuated in the season that an animal has the lowest fat stores. Energetic state may be signaled via leptin, an adipose ...

Environmental experiences during development provide animals with important information about future conditions. Siberian hamsters are photoperiodic rodents that dramatically adjust their physiology and behavior to adapt to seasonal changes. For example, during short winter-like days, hamsters enhance some components of immune function putatively to cope with increasing environmental challenges...

OBJECTIVES The aim of this study was to clarify the chronic toxicological effects of indium-tin oxide (ITO) and indium oxide (In(2)O(3)) on laboratory animals. METHODS Male Syrian golden hamsters were intratracheally administered 3 mg/kg or 6 mg/kg of ITO particles, or 2.7 mg/kg or 5.4 mg/kg of In(2)O(3) particles, containing 2.2 mg/kg or 4.5 mg/kg of indium, twice a week, for 8 wk. Control h...

Siberian hamsters (Phodopus sungorus) exhibit changes in reproductive and immune function in response to seasonal variations in day length. Exposure to short days induces gonadal regression and inhibits testosterone secretion. In parallel, short days enhance immune function: increasing leukocyte numbers and attenuating cytokine and behavioral responses to infection. We examined whether photoper...

BACKGROUND We previously reported that chronic endothelin (ET) receptor blockade ameliorated the survival rate and cardiac hemodynamics in rats with chronic heart failure (CHF) due to myocardial infarction. However, it remains unclear whether ET-1 is involved in the pathophysiology of cardiomyopathy, which is one of the major causes of CHF. Accordingly, we investigated the production of ET-1 in...

The present study includes cloning and expression of recombinant Leishmania donovani histone proteins (rLdH2B, rLdH3, rLdH2A and rLdH4), assessment of their immunogenicity in Leishmania infected cured patients/endemic contacts as well as in cured hamsters and finally evaluation of their prophylactic efficacy in hamsters against L. donovani challenge. All recombinant proteins were expressed and ...

Newborn hamsters were inoculated either i.p. or s.c. with 0.1 to 0.2 ml of CELO. Random-bred (19) and inbred LSH/LAK (8) hamsters from our colony were used. The inoculated animals were weaned and sex segregated at 3 weeks of age. The hamsters were observed until death. Animals were sacrificed by cardiac puncture. Ascitic fluids were collected from the peritoneal cavity by syringe. In general, s...

The circadian mutation duper in Syrian hamsters shortens the free-running circadian period (τ(DD)) by 2 hours when expressed on a tau mutant (τ(ss)) background and by 1 hour on a wild-type background. We have examined the effects of this mutation on phase response curves and entrainment. In contrast to wild types, duper hamsters entrained to 14L:10D with a positive phase angle. Super duper hams...

Hamsters receiving both macrophages exposed to Formalin-inactivated Borrelia burgdorferi (Mphi-FBb) and enriched populations of either immune or naive T lymphocytes developed severe swelling of the hind paws when infected with B. burgdorferi. Swelling was detected 6 days after infection, peaked on day 10, and gradually decreased. Swelling was also observed in the hind paws of hamsters infused w...

Lipopolysaccharide plays a major role in the development of lung injury induced by Gram-negative bacteria, but a protective agent to attenuate the LPS-induced lung injury has not been found. The aim of this study was to examine the effects of niacin on LPS-induced acute lung injury. We administered LPS (Escherichia coli) 0.01 mg.100 g-1 body weight, transtracheally into the lungs of hamsters. N...